1. Technical Field
The present invention relates to a web processing device which cuts a web into predetermined sizes. In particular, the present invention relates to a web processing method and web processing device which form marking patterns, which include visible characters, symbols, or the like, on the web to be cut along a conveying direction thereof.
2. Description of the Related Art
There exists a technique for carrying out marking processing on a web by irradiating a laser beam (laser light) onto the web while continuously conveying the web. Such a technique is proposed in, for example, Japanese Patent Application Laid-Open (JP-A) No. 5-238098.
Various types of conventional techniques have been proposed which are applied to a photosensitive material (such as an X-ray film) which is a web, and which form a marking pattern on the photosensitive material. For example, Japanese Patent No. 3,191,201 proposes setting the laser irradiation time (pulse width) per dot to be at least 30 μsec or more in order to improve the visibility of a marking pattern formed on a photosensitive material.
A photosensitive material such as an X-ray film is cut into photosensitive materials of small widths from a web roll which is wound in a roll form, and is processed into a final form of sheets or rolls of small widths. Among processing devices used in such processing of X-ray films, there are those in which the X-ray film pulled out from the web roll is, while being conveyed, cut along the conveying direction (which is the longitudinal direction thereof) at a predetermined position along the transverse direction thereof, and each of the cut X-ray films is wound into a roll form.
There are cases in which predetermined characters or symbols (hereinafter called “marking patterns”) are formed at positions which are the peripheral edge portions when the X-ray film is formed into sheets for example. After the X-ray films formed in sheet-shapes are stacked up, they are placed at a marking device, and are successively subjected to marking processing while being removed one-by-one, so as to form the marking patterns.
In such a method, the processing of the X-ray film is carried out in two steps: the processing step of carrying out cutting, and the marking step of carrying out the marking processing.
Thus, a method has been thought of in which a marking device is provided at a processing device which cuts a web roll into rolls of small widths or at a processing device which cuts small-width rolls into sheets, and the marking processing is carried out in parallel with the cutting of the web-shaped X-ray film. In this way, the cutting of the X-ray film and the marking are continuous, and can be carried out efficiently.
However, when the X-ray films are sheet-shaped, the conveying speed thereof must be made lower than when the X-ray films are in roll form. Thus, the work efficiency is extremely lowered merely by integrating the cutting process and the marking process.
Further, there are cases in which the laser head, which forms marking patterns on webs such as photosensitive materials by using laser light, has a larger dimension along the transverse direction of the web than the small-width webs do. Therefore, if the laser head is merely provided so as to oppose the respective webs which have been cut to small widths, a larger setting space is needed. This leads to the processing device becoming larger.
Moreover, it is easy for offset in the transverse direction to arise among the webs which have been cut to small widths. Such transverse direction offset of the webs may lead to positional offset of the marking patterns formed on the webs.